Organic chemistry – 14.3 Bonding: structural formulas Flashcard

Bonding
Structural formulas
Outline
Saturation
Degree of saturation
Bonding
Structural formulas
Saturation
Outline
Term: saturated
Term: unsaturated
Concept: saturated compound
Concept: unsaturated compound
Bonding
Structural formulas
Saturation
Term: saturated
– Contains no pi bonds
– no rings
Bonding
Structural formulas
Saturation
Term: unsaturated
– contains at least one pi bond or a ring
Bonding
Structural formulas
Saturation
n
carbon
Bonding
Structural formulas
Saturation
Concept: saturated compound
A saturated compound with n carbon atoms has exactly 2n+2 hydrogen atoms
Bonding
Structural formulas
Saturation
Concept: unsaturated compound
A unsaturated compound with n carbon atoms has fewer than 2n+2 hydrogens.
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Outline
d
Formula of degree of unsaturation
Formula of degree of unsaturation: n
Formula of degree of unsaturation: x
Formula of degree of unsaturation: x (other atoms)
Degree of unsaturation and hybrid bonds
Examples
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
d
degree of unsaturation
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Formula of degree of unsaturation
((2n+2)-x)/2
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Formula of degree of unsaturation: n
carbons
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Formula of degree of unsaturation: x
hydrogens
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Formula of degree of unsaturation: x (other atoms)
x represents the number of hydrogens and any monovalent atoms
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Formula of degree of unsaturation: x (monovalent atoms)
Such as halogens:
F
Cl
Br
I
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Formula of degree of unsaturation: x (oxygen)
Since the number of oxygens has no effect, it is ignored.
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Formula of degree of unsaturation: x (nitrogen)
for nitrogen-containing compounds, replacing each N by 1 C and 1 H when using this formula.
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Degree of unsaturation and hybrid bonds
Indication: one degree of unsaturation
One degree of unsaturation:
presence of
– one pi bond or
-one ring
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Degree of unsaturation and hybrid bonds
Indication: two degrees of unsaturation
Possibilites:
– two bi bonds (two separate double bonds or one triple bond), or
– one pi bond and one ring or
– two rings
and so on.
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Degree of unsaturation and hybrid bonds
Example: one degree of unsaturation
4-Chlorobutene (C4H7Cl)
– 4 carbon, 7 hydrogen
– Number of hydrogen is different.
– each halogen atom (F, Cl, B, I) or other monovalent atom “replaces” one hydrogen atom, so
d= ((2.4+2)-(7-1))/2=1
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Formula
divalent atom
replace one carbon and two hydrogen atoms
Bonding
Structural formulas
Degree of unsaturation of simple organic molecules
Degree of unsaturation and hybrid bonds
example: one degree of unsaturation
Methoxyethene (C3H6O)
– 3 carbons, 6 hydrogen
– each oxygen (or other divalent atom) replaces one carbon and two hydrogen atoms.
– CH2 groups are sometimes referred to as methylene groups
so d= ((2(3+1)+2)-(6+2))/2=1

– Since a divalent atom can take the place of a methylene group, it does not affect the degree of unsaturation, and can be ignored.

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